You can try lowering your burn speed to the slowest that your drive supports (you should always burn CDs and DVDs at your drive's slowest speed). There aren't other programs that will burn the files to an audio CD, only iTunes can do that. There are other programs that will convert the files to mp3 for you though but they record the audio through your sound card. TuneBite is an example.
When I try to burn AAC (m4p) files in the latest version of iTunes the software gets stuck displaying the message Preparing Disc. A progress bar slowly (very slowly) moves across the screen but the burn process never begins. I haven't tried to burn any AAC files in a long time until recently but I know I did not have this problem prior to iTunes 7.
Any ideas? I haven't been able to find much on this issue in the Apple forums or here on iLounge.